SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a3b07cbfdac3ed8c9e02c811d2fb1ae6ef5e35efaed03a1bf5a8bb4a6698c381' 
  AND token = 'vJbr1E+liRdvWtM66WqAljDvMKmlNbfPHe8jivrAUwo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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