SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'da06633a4b5f2ec5509fd691ae21f8104870e7a300546dad57023d969fdd0beb' 
  AND token = 'gz4U1NX4+cuPn1Lb1Ho9f4fbXqPOSh9gytcZ0BAPK0Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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