SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '173426394784f145cc1c29347eb8dff63b6c9fd7a4d505c97cf9b04bf7208346' 
  AND token = 'UXRpeh2HxxfWe0lOwZTofMoh3e/mG/ihUfDfwxrH3IY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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