SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc0711776c6038cba1f4492376400b73958d2b47ab93cfaa32e9db6063626b9c' 
  AND token = 'yVrcXa9199vrtQZ6/M36KVpuer8/IhttBrEI2HPl7+A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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