SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9803c693ef8f13b8cd6a3df585dc2b4f71417345055adb2cb6ded8075eb82199' 
  AND token = 'wUeBxdhNRYcTPYLcmJHqe/1vgd1NSCiK1TXi/BJzq0s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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