SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db34fe930e6f3720342fac6ad6f74f1d4a988249ecea3e7811870fba917e44ff' 
  AND token = 'qVXS/BiMMtkaOhcSEkWou09jlhtACxHWaY+emofbB94=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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