SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af9d3d760632f58cbbf4bf39b6e6f3e92e7fa144c076a7a28c525812d5e83bfa' 
  AND token = 'uVwpO2UQe/7+crl08lcUlRD8Fx39zTli7j+aCH6RmOg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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