SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dcf33c545b6b62643694f4609bc43d61415a50cf5d737473b53b70884bc82a1d' 
  AND token = 'ugGstn5fWV7kkRVlKVKpZIfTCY1exPqtL04m1e/PEKY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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