SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '279bae98b32a36ff324c33eece186a17215400785a3f68b88e464ee3f9c39b93' 
  AND token = 'V41uS3S48zrmHtliVSqTztktR9Iag4YMNJlzfP+FwA8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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