SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'e3440497dba3657278f2f2347fe6b41c41f34988b8f99af41d26057959021752' 
  AND token = 'rUIzUiKUH+IvVNkFP8PVLhwOog7C+FQX7iRSUCpjTxI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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