SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5881db6d1d9f31a8277d025292c9dbb6030d81e7c1f95bad36fc72d92ab91334' 
  AND token = '9UoHWmRY4QBTVg0f3gODYcZWeinImy5zvjBV7MsTFPI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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