SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad1b7ad44eb80a99e37880fdf368110cb36d2b62cf5086cc168c5e29e560a067' 
  AND token = '5en+h3JRddNycAkzaJ06oHyxiDedDMWdA3yP2l7qqiQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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