SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4e69adff5d7673b11f3918e1fa72e007052577f20ccf86d2328c358a5836b271' 
  AND token = 'm+k6iIpaDGZ/Aooq5ibKh8VWsWnSu9lOFap6cIruc5U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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