SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7cb48b48b535a5c6756741403787447dc7291466123f652f9c9453b882b8f58a' 
  AND token = 'CUz4fF6mkbvA6O8GWQQ87xQQgvBDEnnfdq8vY+pkuZA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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