SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ac61b1cf3314270073948f1ff6c2a6135d71c44dc5f58dc6d0d2fac5cca807a4' 
  AND token = 'qrL07EQJ2u02PKwZlo2rErh7+8hYq/2E7Ddd9OtcmgU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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