SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9407efa2f72fdcb0bcc23049f8d10fed09642921237edd7cade9cbbddcdc9186' 
  AND token = 'DD4EDEzSJztzf76an+QeHBJc9LMjYFBLfqwiJgUaSUc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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