SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8fffd3fa899b6bd7e10445e11743ab8a90d45d28ba6d705ab88dcf9922930306' 
  AND token = 'v5ajpTumLYKWPoyjnDuJRFgGgrvmSU/HReOEoURIJVI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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