SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '858c907213f166948ad26f864dd2773494d3788055909548861ccc5452f5adf2' 
  AND token = 'CFO6bsqqQOIx+11WrQQK3bVU1y0MdrlCfopqUTHWcrY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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