SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ffd1671766248e6d6e679473b6097c06046368aca5d1e63025d55efea26f62d' 
  AND token = 'q8+ZW4Cf6hpfOj+BsWPUYXp4NOb6U18azitE0iAzQJs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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