SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '959b49a3f4a71462a684700fdbd35c9c564e8a9642f55ce5382de5d54ebede87' 
  AND token = 'fqxMscwnlKu1+8+fGClHhXi9OMIjxYNcZkX76nOQq6c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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