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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df1b685c92e862e3f4645df9076f7c38be7a6b338001fb31b95bb2dcbc9cb739' 
  AND token = 'eFC6YiMoxwG6a7Y5yHPjv8LNLW2gp3q+1UD13FrVEnU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}