SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f36224e435b43cd8a8ffe37ec03fa985d2921991eed5ea1fa0e1c22b9bf028fa' 
  AND token = 'rMeDMvOTxwhdHRWq2Xs2lNnGkFqSMDnH41//3Izyx60=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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