SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a3f29405670574448cef0d74f800aa97f68e71b4fa0878174e4bc04a58717597' 
  AND token = 'eZ5fopmB2fXvawL4LZXVdoSotnF3khhAYMEKPcB+CIU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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