SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '284c53252fc136555b84a999186773c6cb412edb101626e091e8695c3bda23dc' 
  AND token = 'SY0SZyq+D7MSKxrsknWw9KkJBb9XsNxvR5CKajjqw+o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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