SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b99598d953b06209989a9a96aa3068cea558be40289605f16b06f4f1650352ce' 
  AND token = '8Ml/fyQprJDEmWv7SaY/bP4THtlycXzsw8tqTtlSd9o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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