SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a890fca7619aa9ea86257499564dfa0b1329215a0acf34f5bf2333a0485c209' 
  AND token = 'bz6TXyREdPDc6IBbIfNIzbFR/bOqipBCbKfiXSvOdac=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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