SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '576cf5eb700878aff779e2a70e4b83c281ef91169053f672d622699082695563' 
  AND token = 'V+NzpV0iIM1Zqsfn70st/W5u+WZbrgj7ueUgYq7WiOQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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