SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ee37389674016af08bc30e041e8084d3fc7db1163f09236be2176f3b0dbbf234' 
  AND token = 'txr9UyaFb0cptF0fDrZnEDq4fI9wFKDPCpUrFjl17gU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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