SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6a8727b54fcc04ebb39eba43b2220f49b150ca99be75a4d2a7ae176fe9166485' 
  AND token = 'rDkqp9K1kwfezBb17HMUKyueisxK2tyg8+e5Oz9ekbA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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