SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '702563c22bded0b387714b60a3a28be83872c9b7402cef39eedac2808ddb0476' 
  AND token = 'RcX0elcfMugvBvZWM9m4Njimf9AQI+TLFycHD/ONT8w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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