SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0ce238a8646e2517ad0a77d7bcf1c818d6291d2ef935da33a5b1c2d9c1fdb34d' 
  AND token = 'mNJ2+FYaclKRrqFZrtWk7AGBlaF5l/lJLqRYvZz9hZo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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