SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0928637cf77693ac7495dac1336f01221bb1ddc5df8b4359e38d20bcee40b698' 
  AND token = 'Ghn/sYF84jMUbmDX7aga/ztsfFIOkYbxRbOz5ZBuOkM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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