SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'da21f4a8576bc38e96e598a7633f70be052352a2cef4e01baf6b49ad8cc72b18' 
  AND token = 'ZU/0KihtrO1E6/ULK4tvwtB74mOpkqUX4wKDzR+mZqg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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