SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e0599825856074c29d987dd43cae3efdaa1a61aff47b019a6cd581b762c4c506' 
  AND token = 'DyBcG79Uvym1zXC15H/PlCrlWWvVurM6pPLggkmsA9k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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