SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b42cf63b464c053c4ed9c6208a5ec3be65657f92ff1fd11b6237cbd98c1ef50' 
  AND token = 'KyKDVX1XBWM7m5Eji127MIzTZ8PABKDz3mPMzedotEA=' 
  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"
    }
  }
}