SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6bcadcafd644a08106918099d85e28aec6a52ac2be6bb7c69d1bfff8235cc24b' 
  AND token = 'xpsxE2siMAnbjw+TwshouHzVkLmoitMIEtMeYC63gdI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}