SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1fe69e17a7290187412569e3baf163320fe4d586d33e77804e2234d9590aadcd' 
  AND token = 'xXLJ2nCuKNBz/EyHaFvNelokiN5/cvsjLjXT3azjNuY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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