SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b71efdaed7ea909470d31ebe7e3e6be4148a352e1cb5b499c867305c0f0bb72' 
  AND token = 'GzEswANa+oxkk1yoOy7GG/r5mhP3qcckvpnjawqyQV0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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