SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd18ab39420c71de1c89866e18b5589c9a5054b30e1500d722948ae98b98b541a' 
  AND token = 'egiygifFk+I/HZxHiPbMoT61xxMXb9J5nz8jKau9X9E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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