SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '53b7b7a6f42fd796f383c1a5fae9f1f953cd74bc1722a6b72a28769a300f8b5a' 
  AND token = 'gtqbGaIvio/wrdF2HtaYvMUyJL4Y+CSzMDH6O5GRAzA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}