SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '23dfea21ca16f7c5c5dd250d711d2703872437588a1adea1ea23b30ef52be8c7' 
  AND token = 'EsLcmJE1zxL+dSnfKrw+IOS9HHvnGehRpdrCTmOKMkE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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