SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c23c610cc872699e7d430a4d97ca0dd0fdea34aa551dcd95339f8a0747528d8c' 
  AND token = 'U3mYrBg0r5Nzwcy9I2cwf5L7xe74Ifnj34U+g8dQ6hg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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