SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c6c1abffc9cda1b50a314479628d41068eb8df0447a5108ea32b45a7333d85a' 
  AND token = 'EkqC+LU4UGY+367D//kP3Kl2B6fymzXWd5vIEZR9l64=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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