SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d41dbeb54483bdb746f818ace47be904244649d8de556d484713c9a4d1938a8' 
  AND token = 'uVmFgy6SwfbEX9lDWBgyVsoVZUphTBDxGgOH4YajuN4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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