SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4cd478cd5f2a0d90f73489d6268433ff5f7aaf4d618c25bf654853667bed4798' 
  AND token = 'Ir8aQoGSB1FW5r7SCPCF7Iwj8mM+ZBFW0NvJcYzSSUE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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