SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '99da25466486a72481b249246229a5045cc4222f9480045b80e6363d23612906' 
  AND token = 'VG1TnixrkbVyVABQJzzZ7mcDGrp72QrfpAFKPwEdHXU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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