SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '48df3a839be8d4d072fa1cf4535aaa352e680421231c5bd2ccaa08031d402c19' 
  AND token = 'fNgiayceYa0U1m7zyaDFZKqHDHKjVFRzWy6rqP9tB+c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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