SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4dd65270b78e8a38abdf1593296d1e63c9341152057092a69751bde321db9dc8' 
  AND token = 'ww7QL4zIzmU+dSt2fhTkmU5zV1ZrjVfT1N2qShEb0M0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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