SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '43803f0f216ad3a5c9d5dc125be9dc8549811698d58a84c7f05d91ff1659c7b1' 
  AND token = 'OnfBGC4Xg6/0Bd5O279sKH2mQ/pNZhohpUv4zTGTlTc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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