SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cbf5f9b53962086347ddd674903c2badafe50497f9b4d3c8f5f2878290cb29a6' 
  AND token = '3M8iGHT5Bd1aoeGO8G9E2skblyS+PFZDmmQjGEEGA14=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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