SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9305e70fd414b71becf4d996cd1bea1b0b78cde5ca59104d2e55647fc75502a1' 
  AND token = '0Z2CzL1Qzt0cKqRiZ9Jg2o3j8/vjFXtLH1XPomsGKUM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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