SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ffb3a2a68a7494106a1e5918806c08b17a1e2bc2370eb75db051624c8e4b1375' 
  AND token = 'IGYOjsiGBFuchV1LgbnXNnl6lyn8Vvu0ByPD2JIIyUE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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