SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '68af2df5c15c93e8ae008ad3f339373c197eb0f81a9f39360a7e67cc3ff31ecc' 
  AND token = 'vNVRV+EpZGrKSAwaYjXkosqDOEzBKno+BOLWh8aDszU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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