SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '110c2f5f2d2ca4bb84b4645e1b23976c9d170c8ec1752526ccd96528dbbc17e7' 
  AND token = '3ssDVVu8fGzwRTqZYGUcbhtnFtwJaZ4gNIFDWsh9roU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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