SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '497977309fc8511524ad75c8d396768f466304ff8ed7f2611190321b4b5619e5' 
  AND token = '/CZCodE5OZkTzU0X2PMCz+ITRqWLzVYVO3MJzn/Q904=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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