SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '603ce73d8022940ae3ce903ac91ce9fd39c9229f29215d0b392fb35f7058f006' 
  AND token = 'y/WUJN2piueB193nvFCsJmz007yj8JDZ4YY96kIS7TA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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