SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b3dfea69cdd98551991ad639165846b3990ce49edacb1653aaa9367489ddf61' 
  AND token = 'wLUKfZpBKeK68V5cxGmHxHV0nNl+gmEnnzT07vRnz5c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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