SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5cfa243aa75218e1d1a34bb8cb41f787085740e196b7653ec61d89ef6d1a019a' 
  AND token = 'qzOhktDuuXjoBc0aAy8IZulWXAhBUGXKxVVtOS+wXcg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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