SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03ecab52408ceff729555ddab1b412f0de29a1f10994fe8eb1bccb617037ffb6' 
  AND token = 'eh3grSDMVDrIP2qcikNp0h8HaKtNGynjOjIdOcBHDgk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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