SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b0fe565ef4e752a0de677703b892a078c15ff9424e5da3f33aa84028ef81d2a4' 
  AND token = 'xSeBuA4W01805MhSOIiKHURPY1phejDKeGIseXI2HOY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}