SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '02b233dd734d3d37747cbf943fbf1920467e74fe1da215a2796b046782c21e09' 
  AND token = 'K6ax0v2m69ZOYSG97mWhiJ9RryUmdvez0CQVM09iNR8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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