SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '443a2b46c738324971e602cf25a7f4d4bbc62ce140ba312debade738d482278a' 
  AND token = 'qzfhcktZ2iB1+nGMWvtqhD31DEzuay/fg5WPq6JXbu8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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