SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0708eee3ac61bb51c8223f502982e651faaf2382b4e5955910f61d777e441e89' 
  AND token = 'MMH0ktfwfGlLcpdktsF8wGNXQOb/x5Y6Dbhqqx31G78=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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