SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fa803253f8f2471c331d74734497ca1559bef8126487fb674ac78e9f8781318f' 
  AND token = 'vKy9aZa4wjGcCcxpwwVCYQkwWd8CbJl0UohnUPRoBEY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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