SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e23e7a03b972ddc49f76d850280bd446c3cbda9a069099e8ed043646dee1e3c' 
  AND token = 'E9jjZvogKoH5kPKTIFDISKkM6SVpvjWDOIXdjhasXq4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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