SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '99a615a7e70eee34bef745258ce87fc0a935ff0d0ad93009bae0779005ee7a23' 
  AND token = 'hVNFRqAiUVcVEDGLYD5qMa1gv8QQvWfNum5jyym5Bgo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00064

JSON explain

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